Motor control.



PATBNTED uur '21, 1908.,v

E. `wvfau'-'. MQTOR CONTROL. APPLIOATIGH FILED JULY 25, '1908.7

a slums-anni 1.

mu Q .mwa am. alim No. 377,028. PATENTI-JD JAH, 21,v 190s.

H. l E. wHTE. MOTOR' CONTRO-L.

APPLICATION FILED JULY 25, 1906.

/m/entor Hd'fod .E White FWFJNT FFICE narra, or sonaNncranr'Nnw Yoan, AssioNoR ro GENERAL 'Etnornic- COMPANY, A CQRPORATION OF NEW YORK.

CGNTROL.

Application led July 25. 1906 Serial No. 327,683

equalize the. input to electric motors driving' .varying loads, such as rolling mills, mine-.

hoists, etc., to provide the motor with a heavy fly-Wheel, and with automatic means for lowering the speed ci the motor during periods of heavy load in order to enable the ily-wheel to give up a portion ci the energy which it has stored during light loads.

The object ci my invention is to provide simple and novei arrangement of switches whereby manual control 'of the motor ir u, be' obtained at starting, and eiiicient automatic control lsecured when the motor is up to speed. i

My invention will best be understood by reference to the accompanying drawings, in which e p Figure 1 shows an electric Vmotor provided with controlling` switches arranged in ac.- cordance with my invention; and Z shows a modification of the same.

'ln the drawings lhave shown my invention applied to the control ci -an induction motor.` advantageous for use in connection with induction motors, in which the secondary currents are large 'in amount and of low voltage, is nevertheless not limited to this particular type'of motor.

In Fig. l, A represents an induction motor,

the primary of which is connected through leads c to a source of polyphase current, not shown. p

B represents a fly wheel on the motor shaft. l

C represents collecting-ings ccurcected to the secondary winding oi the motor; Each collector ring is connected to. one terminal of one of the resistances D1, D2 and D3. The other terminals of the resistances are connected to a common conductor d.

E represents a manuelly-operated startmg fswfitch for the motor adapted to energize serially the magnets F1v to r1 15, which control contacts for short-circuiting portions ci the Speciication of Letters PatentG My invention, while particularly.

Patented Jamai, 190:13.y

{ resistances. Mvith switch E in oit-position,

as shown, all ot the ymagnets F1 to F 15 are deenergized, and all of resistances D1, D2 and D3 are in circuit. This .is the starting position of the switch. l/Vhenmoved to its first position, switch E connects the lead e1, from 'finger l, which connected to one terminal .of magnet winding F1, the other terminal of which is connected to the lead e2, whichex- Magnet F1 is thus energized, short-circuiting a portion of resistance D1. In its second by short-circuiting a portion` of resistance D2. As switch E is moved through its other. positions, it serially energizes magnets F3, F1., etc. until all of the resistances are short-circuited.

' magnets G1 and.G2, which, in Fig; l, are

shown connectedl in the secondary circuit of the motor. Magnet 1G1'i's arranged with a greater number of turns, f or in-any other suitable way, so as to respond to'a smaller amount ci current than' is necessary for actuating magnet G1. n lt-jwilll-be'sefen vthat magnets F13; F14, and F15, yinsteadof being connected` directly tothe lead 2y are connected through the contact controlled by magnet G1. Consequentlyi. when the load on the motor rises to asulicientv amount-to cause magnet G1 to pull upitsfcore, magnets F13, F14 and F15 lare de''nergi'ze'd," thereby cutting in a portion of eac-h ofthe'threeresistances.

ily-wheel B to give up a: portion 4of itsfenerg'y to take vcare ot` the eXcessfof-loadff.dfft lload further increases, vn'ragnet'*Gr2 will be therebyl d'energizing magnets F10, F11, .and F12, and cutting .more resistance linto lthe secondary circuit of the vlmotorf. The number of these magnets @r1 and: G2 may' be mfurther reduction of vmotori.speed.i lt-xwill be seen that when either n'iagnet-@1f-orGf2 operates, its immediate-effect is to .cutresistance into the secondary circuit, ano

The magnet Works any suitable source of current, to contacttends to the other terminal ofthelsource.

creased, if desired,so-astoobtain astillI position switch E energizesmagnet F2, therel'liile switch E is being thus moved, motor A l energized suliciently yto vdraw' up its OOIef` thereby to decrease the amountoffcurrent i' '.tlowing in that circuit.

conseguently tend to drop its corey ag'ain. In or er to prevent this, I provide the cores of the magnets G1 and G2 with dash-pots g1 and g2, which retard vthe closing ofthe con- 5 tacts controlled by these magnets, so as to give the motor time to .slow down until the secondary current has again reached a sufficient amount to hold the magnet contacts open. l

In Fig. 2, I have shown an arrangement in which dash-pots or similardevices are not required, since, in the arrangement of this figure, the operation of magnets G1 and G2 does not directly affect the amount of cur-l rent passing through them. The arrangement shown in Fig. 2 differs from Fig. 1 only in the connections employed for energizing the magnetsGl and G2. In this figure these magnets, -instead of being connected in the' secondary circuit of the main motor-A, arestood from an inspection offthese drawings,Y

\ and from the description that has been given Yabove of the arrangement of Fig. 1'.

' While I -haveshown'the ily-wheel B as independent of the motor structure,l it is obvious that-it may-be combined with the y'rotor of the motor, or with any part ofthe driven load, if desired. Conse uently,l when I employ` the term' iiy-whee in fthe'appended claims, I desire to be understood to include any mass having a high moment. of inertia, 'whether 'included in the motor structure ornot. Furthermore, I do not desire `to limit myself to the particular construction and-arrangementof parts here shown;

but -aim 4 in the appendedv claims to cover-all] modifications which'iare within'the scopeo'f ,my invention.

What I claim as new and desire to Secure -by Letters Patentof the United States, is;

` 1. In combination with'anelectric motor, a ily-wheel driven therebyia-starting resistance therefor, a manually Vcontrolled 'switch-forcutting said resistance out of circuit', and a' plurality ofl magnetically-actu- -ated switches arranged 4to .out portions ofsaid resistance into circuit, the actuating vmagnet windings ybeing connected and Aarranged to actuategsaid switches successively when the load onthelmotor exceeds predetermined amounts. l2'. In combination with an electric motor,

a Vily-wheel driven therebygafstiiiijtingretac-ts, land means for automatically den'er-, 1,310

smoes sistance therefor, manually controlled switch for cutting said resistance out of circuit, and means controlled by the load on said motor for cutting portions-of said resistance successively into circuit vwhenthg'ay load on the motor exceeds predetermined amounts. 3. In combination .with an eleCllric" Iiiotor, a ily-wheel driven thereby, a starting"resistv ance therefon-a plurality offmagnetically 75. actuated contacts for short-circuiting por- .l tions of said resistance, a manually-operated starting switch controlling 'the' actuatingv magnets 'for said contacts, and means con'- trolled by the load on the motor'controlling a portionof said magnet windings.l

4. In combination with an electric motor, a illy-wheel driven thereby, a starting resist- 'ancetherefon a plurality of magneticallyactuated contacts for short-circuiting portions of said'resistance, a manually-operated starting switch controlling the actuating 'magnets for said contacts, magnetically-actuatedlmeans controlling said magnet Windings, and connections for supplying to' the" actuating winding ofsaid controlling meansv a current varying withtheload on the motor. 5. vIn combination with an electric motor, a fly-wheel driven thereby, a lstarting resistance, a plurality of magnetically-actuated contacts for short-circuiting portions of said resistance, a manually'- operated starting switch forserially energizing the actuating windings of said contacts, and means for automatically denergizing a portion of said windings when the load ontlie motor exceeds .-aA predetermined amount.

6. Inl combination withan electric motor, a ilywheel 'driven thereby, a starting resistance, a plurality of .magnetically-actuated contacts for short-circuiting portions of said resistance, .a manually.- operated starting switch for serially energizingthe actuating vwindings of said contacts, and means for-aultomatically serially denergizing a` ortion of said windings whenthe load on t e :motor exceeds predetermined amounts.

7 ',"In combination, an induction motor; a` fly-wheel driventhereby, a resistance in 'the vsecondary circuit of said motor,A` a plurality'-1.15',

' of in ag'fnetically-actuated 'contactsfor short-.- circuiting portions of said. resistance, a manually-operated starting switch control-Y linfT the actuating ma nets forv Said contacts,

and'meanscontrolle'fIby theload on the 120 motor controlling a portion :oisaid'magnet' 8. In combination, an induction motor, a fly-wheel driven'thereby, a resistance in the secondary circuit of said inotoiilfaplurality 125 of magnetically-actuated contacts for. shortcircuiting portions of said resistance, a manually-operated starting switch for serially energizing the actuating windings of said conpmi ' smoes 3 a portion of said windings when the load on the motor exceeds a piedetermined amount.

Q. ln coinbiifiation, an induction motor, a ily-Wheel driven there y, a ifesistance in the secondary circuit of said inotoi, a manuallycontrolled etating 'switch' for cutting saidv resistance out of circuit, ainagnetically-ac Jmatedswitch for cuttinf a portion of said. resistance into circuit, and connections for supplying to the actuating Winding of said switch a current varying with the load on the motor.

10. In combination With an electric motor, a Fly-'Wheel driven thereby, a resistance in circuit therewith, magnetically actuated contacts foi" shoit-eiicuiting portions' of said insistance, tWo switches jointly controlling' the actuating Inagnets'for'said contacts,

Saidevvitches being controlled one by hand and the othei1 automatically by the load on the motoi.

1l. In combination with an electric motor, a ily-Wheel driven thereby, a resistance in 'circuit therewith magnetically actuated contacts for shoitecircuiting portions of said resistance, and two switches jointly contiolling the actuating magnets for said contact., said switches controlled one byhand and thiV other magnetically, and connections for supplying to the controlling magnet of the latter switch a Current varying with the load on the motor.

'In Witness Wheeol have heieunto setv 

